JPH0761881B2 - Device for adjusting the shape of optical substrate - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for adjusting the shape of an optical fiber preform, and more particularly to a shape that is constant along the length of the preform rod. A method and apparatus for adjusting a preform rod used in a rod and tube process for providing an optical fiber preform having the same.

Description of the Prior Art Increasing demand for optical fibers has stimulated efforts to improve the productivity of known MCVD processes (US Pat. No. 4,217,
See 027). However, the speed of the MCVD process is limited by the wall thickness of the substrate tube on which the deposition is being performed.
In order to obtain an optical fiber with optimum shape and optical properties, it is necessary that the core-to-clad mass ratio of the preform be within a defined range. In order to increase the amount of the base tube in order to obtain a larger preform, it is necessary to thicken the wall of the base tube. However, when the tube wall of the substrate tube is thickened, the thermal conductivity to the reaction gas is lowered and the time required for the deposition of each layer of glass particles is increased. If the tube wall of the substrate tube is too thick, incomplete heat conduction occurs, resulting in the formation of bubbles or incomplete sintering.

One way to increase the productivity of the MCVD process is to first make a preform with a larger core-to-clad mass ratio. The preform is inserted into a glass tube used as an outer chiral tube, and the outer clad tube is collapsed into the preform. This is called rod tube technology. It is desirable to minimize the increase in eccentricity of the preform core due to the outer cladding.

If the inner cladding is not sufficiently vertical, difficulties will occur when inserting the rod into the tube. This also causes problems when the tube is co-loaded onto the rod. At the current strength test level, contact between the inner surface of the tube and the preform is not a problem. But the radius matters. The radius difference between the outer clad tube and the inner clad preform should be minimized. Otherwise, the eccentricity of the fiber core drawn will be large, limiting the optimum splice between fibers.

Verticalizing fiber optic preform tubes is not a new issue. See, for example, U.S. Pat. No. 4,477,273 for methods and apparatus used in the production and verticalization of fiber optic preformed tubes.

There is a need, but has not yet emerged, for a method and automated equipment available in the prior art that produces a preformed rod that is sufficiently vertical to be successfully inserted into the tube in the rod tube process. Such methods and devices need to be applicable to existing devices and controllable for a variety of conditions.

SUMMARY OF THE INVENTION The aforementioned conventional problems can be overcome by the method and apparatus of the present invention. A long substrate made of glass material and used as a raw material for optical fibers is rotatably supported about an axis of rotation and continues to the end. Then, the substrate is rotated about the rotation axis. The force machine is moved toward the substrate and moved in the axial direction of rotation. And during that time the substrate is rotated until it engages the force machine. A signal is generated when the forcer reaches a portion of the outer circumference of the rotating substrate. In response to this signal, the movement of the force applying machine in the rotation direction is stopped.

When the base material is not circular or its cross-section leads to the end of the base material and is offset from the rotation axis, when the base material rotates, a part of it approaches the rotation axis rather than the force machine, and it is applied to the base material. There is a gap between the power machines. Then, the force machine can move in the vertical axis direction. This gap in the force machine produces a stop signal.

When the substrate is rotating, each cross section of the substrate is completed if the generation of the signal is maintained within the time during which the part of the outer periphery of the substrate and the force applying device are continuously engaged. As a result of this process, the substrate has a longitudinal cross section, a circular cross section that is sufficiently vertical in the longitudinal direction, is well aligned with the axis of rotation, and is concentric with the longitudinal axis.

A device that produces a high-quality optical glass material substrate that is sufficiently vertical and circular is designed to support the equipment that supports the substrate so that it can rotate about an axis of rotation through the ends of the substrate, and the lengthwise portions of the substrate It consists of equipment for adding. The forcer is held movably in a first direction toward the axis of rotation of the substrate and is normally biased in the first direction. In addition, in the equipment, while the force machine is moving toward the rotation axis, it can also be moved in the direction along the rotation axis. The signal generator is usually the first
Is biased in a second direction opposite to the direction.

In operation, the force machine advances toward the axis of rotation of the substrate, which continues until a portion of the rotating substrate and the force machine engage each other. A signal generator is moved in a first direction to provide a control signal to a facility connected to the force machine. The signal continues while the force machine engages the substrate. During rotation, if any part of the circumference of the substrate is oval or the cross section of the substrate deviates from the axis of rotation passing through the end, the force machine is disengaged and biased towards the axis of rotation and stopped. Produces a signal to It is assumed that each vertical portion of the substrate is sufficiently vertical and circular when the signal is generated continuously for at least a fixed time. When this condition is satisfied, the control equipment stops the advance of the power generator toward the rotation axis. This fixed time is determined to be the same as the meshing with a part of the outer circumference of the substrate during the movement of the loader to the substrate.

In one embodiment, the method and apparatus of the present invention is used for the verticalization and production of high quality glass preform rods after the deposition of the glass forming material within the tube and the collapse of the tube into the rod. . However, the method and apparatus may be used elsewhere, for example, in full collapse mode. At this time, the verticality and circularity of the preform rod are controlled at each stage of the collapse.

Description of Embodiments Referring to FIG. 1, an apparatus 20 comprising a verticalization and generation apparatus 22 is shown. The device 22 has certain geometrical properties and therefore preform rods 24 with specific optical properties.
It is used to produce long glass substrates such as. Their characteristic is that they have a sufficiently vertical axis, that the cross section at each point along the axis is sufficiently circular and that they are arranged concentrically to the axis.

Device 20 also includes a device for heating a glass substrate tube (not shown) to provide a glass preform rod 24 from which the optical fiber is drawn. The aforementioned U.S. Patent No. 4,27
See issue 1,027. The heating of the glass tube occurs while the gas reactants are being injected into the tube. US Patent No. 4,
See 276,243.

The device 20 typically includes a lathe 32 having a headstock 33 and a tailstock 34. The headstock and tailstock are used to support the rotatable end of the glass tube so that it can rotate about an axis 35 which leads to a shaft (not shown) of the lathe. The end of the glass tube is held on the shaft of the lathe 32. Lathe 32 is carriage 36
Also includes. It is mounted for relative movement along a lathe between headstock 33 and tailstock 34. Mounted on the carriage 36 are the torch device 40 and the verticalization generator 22. The torch device 40 is used to create a stream of combustible gas to create a flame that directly hits the glass tube.
By limiting the heat from the combustion gases to a certain surface area of the tube, the torch device 40 creates a tropical zone 41 (see FIG. 2) with a temperature distribution at the surface of the tube. Relative movement of the torch device mounted on carriage 36 with respect to the gas tube results in tropical movement along the length of the tube.

A torch device suitable for such use is a U.S. Pat.
231,777 and stand 4,477,244. Torch device
40 includes a housing 42 supported by a bracket 43 which is supported by posts 45 mounted on carriage 36. Mounting the torch device 40 so as to allow relative movement with respect to the centerline of the lathe 32 leading between the headstock 33 and tailstock 34 provides some degree of containment of the substrate tube. Tube containment is useful for controlling the temperature distribution along a continuous section of glass tube as the torch device moves relative to the rotating tube in deposition mode.

After the substrate tube goes through the deposition mode, it is collapsed onto the solid rod. This reduces the rotation speed from 75 rpm to 20 rpm,
This can be done by raising the tropical temperature to about 1800 ° C. In the half cycle of the collapse mode, the steps are performed from right to left as shown in FIG. The tube is then clamped near the tailstock 34 and further collapsed from left to right.

Next, the preform tube verticalization generation device 22 will be examined.
As can be seen from FIGS. 1 and 3, a forcer in the form of a contact device 50 is arranged next to the torch device 40. In one embodiment, the contact device 50 is graphite.
Including roller 52. Roller 52 is mounted in a fixed position on bearings 54-54 which are supported by housing 56. The contact device can also take other forms, for example in the form of a metal tube. Furthermore, when wear occurs at any position, the roller can rotate in the other direction with bearings.

Roller 52 is mounted in a device designated by the numeral 60 which is supported by a lathe carriage. As best seen in FIG. 3, the device 60 includes a gearbox 62 driven by a stepper motor 64. Extending from the gearbox is a drive screw 66 having an upper end that engages an internal screw mounted on a platform 68. Movement of platform 68 is accomplished through four rods 70-70 connected to the underside of the platform. The rod is mounted in a hole in the gearbox for reciprocal movement.

Platform 68 has cantilevered base 72 with stanchions 74
And a U-shaped end 76 is placed. Top 78 of base U-shaped end 76
The first is mounted on and insulated from
The electrode 80 which is an electrical connection means of. The electrode 80, which is an electrical connection means, includes a lower portion 82 extending to a cantilever base 72.

Mounted on the pillar 74 is an arm 84. An electrode 86, which is a second electrical connection means, is mounted on one end of the arm 84, extends to the first electrode 80, and is insulated from the arm 84.
The upper part of the second electrode 86 is about 0.018c from the lower part of the first electrode 80.
m away.

A balance weight 88 is placed on the arm 84 between the post 74 and the second electrode 86. As one specific example, the distance from the end 85 of the arm to the center of the strut is twice the distance from the center of the strut to the opposite end of the arm. As shown in FIG. 3, the balance weight 88
Causes the end 85 of the arm to be biased downward. The downward movement of the end of arm 84 is controlled by an adjustable stop 89 having an upper end that engages the lower surface of arm 84.

A pedestal 96 is mounted at the end 92 on the opposite side of the arm 84. The cradle 96 is a housing in which the roller 52 is mounted
Used to rotatably support 56. As can be seen in Figure 3, the pedestal 96 is arranged on the arm 84. Therefore, the longitudinal axis 100 of the preform rod 24 supported between the headstock 33 of the lathe 32 and the tailstock 34 coincides with the lateral centerline of the roller. Balance weight 88 causes roller 52 to be biased upward, as shown in FIG. Recall that the end of the preform rod 24 is held on the shaft of the lathe 32 and coincides with the axis of rotation of the shaft.

As can be seen in FIG. 3, the device 22 generally operates to raise the roller 52 with the platform 68 moved upwards. When the roller 52 engages the preform rod 24, the arm 84 is rotated in the counterclockwise direction as shown in FIG. This causes the second electrode 86 to move upward and into contact with the lower portion 82 of the first electrode 80, completing the electrical circuit (not shown) that controls the stepper motor. Because of the position of the arm post 74, the roller 52 moves about 0.005 cm-0.008 cm further after engaging the preform rod, causing the second electrode to pass upward through the gap of 0.018,
Contact the first electrode 80.

Electrodes 80 and 86 have two functions. Not only do they make contact with each other to form an electrical circuit, but effectively stop the upward movement of the end 85 of the arm 84.

Electrodes 80 and 86, which are electrode-like connecting means, are connected to a programmable controller 90 connected to a step motor.
The controller 90 moves the platform 68 upwards,
Then, the upward movement is stopped according to the approach of the electrodes.
In one embodiment, the vertical generator 22 of the apparatus 20 includes equipment that contacts the preform rod 24 and produces a surface having a temperature well below that of the preform rod. The housing 56 is used to hold cooling water, such as deionized water provided by a water pipe (not shown) in the arm and cradle. Water reaches the surface of the roller 52, cleans the surface that contacts the tube, and prevents the roller from sticking to the preform rod. Water overflows the side walls and falls into an underlying drainage tray (not shown). Also water is a roller
It forms an interface between 52 and the rod and functions as a cushion to prevent damage to the rod surface. In the manufacture of preforms using the device 20, the glass tube is placed on a lathe 32, one end of which is supported by a headstock 33 and the other end of which is supported by a tailstock 34 by a welded joint (see FIG. 1). Connected to 97. When the torch device 40 is moved from the headstock 33 toward the tailstock, the substrate tube is rotated. In each stage, the dope reactant is injected into the tube from the headstock, and the used gas is discharged from the tailstock end. U.S. Patent No. 4,278,459
See issue.

In one embodiment, the precipitation mode is followed by the first half of the collapse mode. Then, the tube wall of the tube is tightened on the tailstock side. This prevents water vapor and other impurities from entering the tube during the collapse. Then perform the remaining collapse mode steps in the opposite direction.

In the collapse mode, when the torch device 40 is moved from the headstock to the tailstock and from the tailstock to the headstock, heating occurs at a higher temperature than during deposition. At the end of the second half of the collapse mode, carriage 36 immediately returns to the tailstock for the next cycle.

After the substrate tube is collapsed onto the solid preform rod 24 in collapse mode, the graphite roller 52 is moved upward by the programmable controller 90 to contact the rotating preform rod 24 adjacent the tailstock 34 (Fig. 4). reference). Its vertical position is a function of the rod's cross-section trajectory. The roller 52 is partially pushed by the preform rod, and the tropical torch device 40 centerline 101
Slide the soft glass while moving a certain distance after "d" (see Figure 2). The rollers 52 are effective in aligning the rod with the axis of rotation between the headstock 33 and the tailstock 34, if desired. Therefore, the roller 52 is used to facilitate longitudinal growth of the preform rod and to be placed sufficiently concentric with the axis of rotation between the chucks of the lathe 32. In the verticalization and production mode, the rotation speed of the preform rod 24 is about 75 rpm.

The parameters that are important in the method of verticalizing and producing the preform rod 24 are the reciprocating speed, the rotating speed of the lathe shaft and the preform rod against the tropical of the contact device 50.
24 is the contact position. The temperature of the glass in the tropics is also important. This is a function of the rate of delivery of hydrogen and oxygen to the torch device 40. As one specific example, the delivery of hydrogen to the torch device 40 is 130 liters per minute and the delivery of oxygen is 65 liters per minute.

A tropical zone 40 is formed around the torch device 41 as the torch passes through the rod. But its center is usually the torch centerline 10
Not in 1 and later than that (see Figure 2). The distance d that the maximum temperature point lags the torch device 40 is a function of the speed of the torch device. The faster the speed, the greater the delay distance. As long as the preform rod 24 is thick and the torch device moves along the rod, the tropical lags the torch device.

The contact device 50 should contact the preform rod 24 where the glass is sufficiently soft and can be reformed. Also, the torch device and contact device must be arranged so that the glass can maintain its shape after contacting the roller 52. The point of contact should then not be where the glass is hot enough to destroy its shape.

The roller 52 can be a reference to the centerline 101 of the torch device 40 because it is difficult to determine the location of the tropics (see FIG. 2). Center line of torch device 40 and center axis 105 of roller 52
The distance "d" between and is called the lag distance, which appears in the vertical direction of the glass soft enough to reshape and does not affect the non-soft layer inside the preform. Also when the graphite roller moves to the next increment along the preform rod,
The increments contacted by roller 52 need to cool sufficiently to keep reformation. In one embodiment, the water flowing to the graphite roller 52 provides an ideal cooling zone, creating a preform rod that is gradually verticalized. In one embodiment, the distance "d" is on the order of 3.5 cm. If the distance exceeds a certain range, the glass contacted by the roller 52 will be too cold to reform. Water cooling of the roller 52 also prevents the roller from sticking to the glass and is effective in flushing the erosion caused by the flame out of the tube.

The method of contacting and disengaging the loader or roller 52 with and from the preform rod 24 is important for verticalizing and reshaping the preform rod. As can be seen in FIG. 4, the rollers 52 are moved to the first stage 107 when the carriage 36 moves along the lathe table at a speed of 8-10 cm / min. During this time, the preform rod 24 on the lathe is rotated at a rotational speed of about 75 rpm. Another way of expressing the speed of rotation, and a more meaningful way to understand the invention, is to rotate the preform rod 24 0.5 times in 0.4 seconds.

The first step 107 in FIG. 4 is easily reached by the roller 52. This can be done by controlling the stepper motor 64 through the programmable controller 90 and moving the platform 68 in the direction of the preform rod axis of rotation to a position indicated by "X". Position "X" always moves away from preform rod 24 beyond the maximum possible trajectory of any preform rod. The method of the present invention reshapes the preform rod 24 to have a cross section that is nearly the same as it was prior to reshaping and to be more circular. Further, as described above, the vertical axis 100 of the reformed preform needs to be sufficiently vertical and the cross section needs to be arranged concentrically to the axis.

The stepper motor 64 is controlled to move the roller 52 first in cross mode to the first stage 107 and then to the second staircase shown in fine mode 109. In the normal fine mode, the step motor 64 is controlled to move the roller upward by about 0.0036 cm in one step. However, in the gross mode, a multiplier is used, and one step in the upward direction is about 0.0108 cm. Roller 50 in gloss mode
Is used to quickly move the reference position "X" to the first contact point of the preform rod. Initially, the preform rod 24 is in the position shown by the solid line in FIG. 4 and the trajectory with respect to the axis of rotation 35 is shown in FIG. The first point of contact with the preform rod is only on one side of the pinch-off region (see Figure 4). As you can see from Figure 5,
The preform rod 24 has some offset so that when the preform rod is pivoted it makes a slight orbit.

After initial contact of the roller 52 with the preform rod, and while the preform rod is orbiting (5th
In the fine mode, the roller is moved upward by 0.0036 cm step by step. The upward step increments are approximately at 0.1-0.2 second intervals.

A search of 0.4 seconds is performed in fine mode. After the roller 52 first contacts the preform rod, the roller is moved about 0.005-0.008 cm toward the preform rod. As a result, the second electrode 86 passes through the gap of 0.0018 cm and contacts the first electrode 80. When the roller 52 makes continuous contact with the preform rod 24 for 0.4 seconds, which corresponds to half the 360 ° rotation of the preform rod, but with a circular cross section, the axis is well vertical, and the main axis of the lathe 32. It is assumed that the center line of the rotary shaft 35 passing through the table 33 and the tailstock 34 coincides. This contact is made when the carriage 36 moves in a direction along the preform rod at a speed of about 9.6 cm / min.
The controller 90 performs a 0.4 second search about 12 times per second.

At this time, several options are available. For one, the roller 52 holds the existing level with respect to the axis of rotation 35 and makes no further adjustments. In a modified version of this, the roller 52 is moved upwards allowing re-contact with the preform rod 24, but disengagement occurs when the roller crosses the rod. Normally both produce good preform rods. However, as can be seen in FIG. 4, if for some reason the roller's initial contact point with the preform rod 24 is further to the left, the roller at some fixed point relative to the axis of rotation in the neckdown region is made of glass. It is moved in the direction of mass increase and damages the glass.

In one embodiment, there is a certain cycle of contact and disconnection between electrodes 80 and 86. After 0.4 seconds of search is satisfied, there is a rest of about 5 seconds, during which the carriage 36 is about
Move forward 0.8 cm. After 5 seconds, platform 68
Is moved downward, the contact of the roller 52 with the preform rod is stopped, and the search condition for 0.4 seconds is not satisfied. The electrode 86 is separated from the electrode 80. Thereafter, ie, carriage 36 is moved along preform rod 24 and roller 52 is restarted for the next cycle including a 0.4 second search. In other words, after each 0.4 second contact of the roller 52 with the preform rod, the stepper motor 64 is controlled to move the roller away from the preform rod, so the 0.4 second condition is not continuously met. Doing so, when advancing the carriage along the preform rod until the 0.4 second condition is met again,
Step motor 64 is platform 68 and roller 52
Is controlled to move upward. As a result, preform rod formation is monitored and continuously adjusted.

Can be further devised. If each 5 seconds roller
If 52 is kept at a constant distance from axis 35, the roller will move away from the preform rod due to the remaining trajectory.
Then, for example, the controller 90 again moves the roller upward to contact the rod.

What is important is that as roller 52 contacts the preform rod, the trajectory of the rod becomes smaller and smaller. In one embodiment, two reforming stages are used. The preform rod then has the required geometrical properties, and the longitudinal axis of the preform rod 100
Substantially coincides with the axis of rotation 35 (see the positions of the dotted lines in FIGS. 4 and 5).

Referring to FIGS. 6 and 7, a preform rod 24 having a significant offset is shown. The initial formation of the preform rod is shown by the solid line in FIG. Similarly, roller 52 is moved upward from position "X" to contact the rod in gross mode 107. However, because it is biased,
Fine mode 109 is 0.0036 until 0.4 seconds search is satisfied
Steps well beyond cm are required. This is because the orbit of the rod cross section is further away from the position of the roller than the center line of the shaft (see the rod orbit indicated by the solid line in FIGS. 6 and 7). Also from FIGS. 8 and 9. As can be seen, the preform rod 24 can also have a larger offset, which widens the trajectory. In such a case, the fine mode 1 is set until the 0.4 second search, which indicates that the rod is vertical, is satisfied.
09 requires bigger steps. Referring to Figures 9A, 9B and 9C, the roller 52 at several positions along the lengthwise direction.
And the relative position of the preform rod 24 is shown.
As you can see by comparing Figures 9A and 9B, the orbit has become smaller and is no longer shown in Figure 9C. In the preformed rod 24 after reforming shown by the dotted line in the center of FIG.
The vertical axis corresponds to the rotation axis 35. In Figure 10, the roller
The relative position of 52 and the offset portion of the preform rod is shown. When the roller 52 is moved to the right, it straightens the rod and forms it to have a circular cross section.

Figures 11 and 12 show the reshaping of the rounded distorted preform rod and the loader, eg roller 52. As can be seen in FIG. 11, the preform rod is oval at some point, and therefore when it is rotated it leaves the roller 52 at the lower perimeter. This disengagement causes the controller 90 to move the platform upwards until the roller 52 and preform rod 24 make contact again.

As can be seen in FIG. 13, after verticalization, the reformed preform rod 24 is replaced by the outer clad tube 120.
, And the tube is co-plased to the rod. The optical fiber is then drawn from the outer cladding rod in a known manner.

EFFECTS OF THE INVENTION It should be understood that the arrangements described above are merely embodiments of the present invention. Other arrangements may be invented by these techniques, which include the principles of the invention and are within the spirit and scope of the invention.

[Brief description of drawings]

1 is a perspective view of an apparatus for providing a fiber optic preform rod according to the method of the present invention; FIG. 2 is a distribution map of a tropical zone across a portion of a torch device, a portion of a vertical generator and a preform rod; 3 is a cross-sectional view of a portion of the apparatus of FIG. 1 used to reform the preform rod; FIG. 4 is a view of the preform rod during reshaping with a vertical generator roller; FIG. Fig. 4 is a sectional view of the preform rod being rotated; Fig. 6 is a diagram of a preform rod having an offset when reforming is performed by a roller; Fig. 7 is a diagram showing the preform rod of Fig. 6 being rotated. Fig. 8 shows the preform rod with a large offset; Fig. 9A, 9B and 9C show the rod in Fig. 8 at different longitudinal positions; Fig. 10 Is a preformed rod with a large offset FIG. 11 and FIG. 12 are sectional views of a preform rod having an oval shape; and FIG. 13 is a preform rod prepared by the method and apparatus of the present invention to an outer clad tube. It is the figure inserted. 20 …… Device 22 …… Generator 24 …… Preform rod 32 …… Lathe 33 …… Headstock 34 …… Tailstock 35 …… Axis 36 …… Reciprocating stand 40 …… Torch device 41 …… Tropical 42… … Housing 43 …… Bracket 45 …… Strut 50 …… Contact device 52 …… Roller 54-54 …… Bearing 56 …… Housing 60 …… Device 62 …… Gearbox 64 …… Step motor 66 …… Drive screw 68… … Platform 70-70 …… Rod 72 …… Cantilever base 74 …… Post 76 …… U-shaped end 78 …… Upper part of U-shaped end 80 …… First electrode 82 …… Lower part 84 …… Arm 85… … Arm end 86 …… Second electrode 88 …… Balanced weight 89 …… Adjustable stop 90 …… Programmable controller 92 …… Terminal 96 …… Catchboard 97 …… Exhaust pipe 100 …… Preform rod longitudinal axis 101 …… Torch device center line 105 …… Roller center axis 107 …… First stair 109 …… No. 2 stairs 120 ... Outer clad tube

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor William Donald O'Brien Genia United States, 30247 Georgia, Lilburn Francis Court 4483 (56) References Japanese Patent Publication No. 59-501064 (JP, A)

Claims (5)

[Claims] 1. Means (33, 34) for rotatably supporting the end of a preform rod (24) such that the end of the preform rod (24) can rotate along an axis of rotation (35) extending through the ends thereof. An optical substrate comprising: a means for rotating the preform rod along the rotation axis; and a heating means (40) for making readjustment when the preform rod engages with the roller (52). In the device for adjusting the shape of, a roller (52) that extends across the rotation axis and engages with the preform rod, and moves the roller and the heating means along the rotation axis of the preform rod. A transport device (36) for moving, an arm (84) having first and second ends with respect to the roller (52) supported at the first end thereof, and separating from the rotation axis of the preform rod. , Approaching A reciprocating means (68) for rotatably supporting the arm so that the arm can pivot, and a first electrical element disposed on the reciprocating means adjacent to the second end of the arm. A connecting means (80) and a second end of the arm, spaced apart from the first electrical connecting means, through a gap between the first electrical connecting means and the first electrical connecting means; The first electrical connection means when moving in the direction, the reciprocating means moves toward the rotation axis of the preform rod, and the roller moves to engage the preform rod, A second electrical connection means (86) for engaging one electrical connection means, when the roller initially exerts a force in a direction towards the axis of rotation and the preform rod is released from the roller. , The second electrical connection means is the first electrical connection Bias means (88) for separating from the step, and the reciprocating means slightly moves and engages the roller in the direction of the preform rod to move the reciprocating means toward the rotating shaft. To interrupt
It consists of a control means (90) for controlling the roller so that it continuously engages with a predetermined outer peripheral portion of the preform rod, and has a cross-sectional area of approximately the same cross section in the major axis direction and a substantially circular cross section. An apparatus for adjusting the shape of an optical substrate, which is characterized in that an elongated glass preform rod substantially concentrically oriented is obtained. 2. The arm is pivotable about a fulcrum above the reciprocating means, and the distance from the second electrical connection means to the fulcrum and from this fulcrum to the end of the first end of the arm. The distance is that the roller moves downwards by fully engaging the preform rod and the roller,
Optical substrate according to claim 1, characterized in that the second electrical connection means are arranged such that they move through the gap and engage the first electrical connection means. Device that adjusts the shape of the. 3. The first and second electrical connecting means prevent downward movement of the roller after the roller is engaged with the preform rod, and the first electrical connecting means. The shape of the optical substrate according to claim 2, wherein means for restricting movement of the second end of the arm in a direction away from is attached to the reciprocating means. apparatus. 4. The control means manages the passage of a predetermined time after the roller engages with a predetermined outer periphery of the preform rod, and the force applying means (50) controls the preform rod. Disengaged from
Immediately after that, the apparatus for adjusting the shape of the optical substrate according to claim 3, wherein the apparatus is controlled to move toward the preform rod in the next operation cycle. 5. The control means is from an axis of rotation as the roller moves along the length of the preform rod after the roller engages a predetermined outer perimeter of the preform rod. The device for adjusting the shape of an optical substrate according to claim 3, wherein the device is controlled so as to be held at a fixed distance.